Cam-operated periodic switch assembly with improved camshaft sleeve and independent cam follower

ABSTRACT

A contact-breaker assembly for use in ignition distributor includes, an annular baseplate arranged to be secured within the casing of an ignition distributor with the camshaft of the distributor extending through the hole in the baseplate and a second plate mounted for pivotal movement on the baseplate, and including a hollow bearing sleeve surrounding the camshaft and spaced therefrom. A body surrounds the bearing sleeve and is journaled for angular movement thereon about the axis of the sleeve, a fixed contact being secured to the body, and a cam follower being engageable with the camshaft, in use, through apertures in the body and the sleeve. A movable contact is resiliently urged into engagement with the fixed contact and is movable out of engagement with the fixed contact by by the cam follower in response to rotation of the camshaft relative to the cam follower.

United States Patent 1,200,627 10/1916 Lang Inventor Norman Alfred Jukes 16 Norman Road, Walsall, Staffordshire, England Appl. No. 30,559 Filed Apr. 21, 1970 Patented Nov. 23, 1971 Priority June 12, 1969 Great Britain 29,75 1/69 CAM-OPERATED PERIODIC SWITCH ASSEMBLY WITH IMPROVED CAMSI'IAFT SLEEVE AND INDEPENDENT CAM FOLLOWER F; mury Examiner-.1. R. Scott Attorney-Holman and Stern ABSTRACT: A contact-breaker assembly for use in ignition distributor includes, an annular baseplate arranged to be secured within the casing of an ignition distributor with the camshaft of the distributor extending through the hole in the baseplate and a second plate mounted for pivotal movement on the baseplate, and including a hollow bearing sleeve surrounding the camshaft and spaced therefrom. A body surrounds the bearing sleeve and is journaled for angular movement thereon about the axis of the sleeve, a fixed contact being secured to the body, and a cam follower being engageable with the camshaft, in use, through apertures in the body and the sleeve A movable contact is resiliently urged into engagement with the fixed contact and is movable out of engagement with the fixed contact by by the cam follower in response to rotation of the camshaft relative to the cam follower.

PATENTEUN 2 3.622.715

SHEET 1 BF 2 INVENTOR RNEYS w wwk,

PATENTED 2 3.622.715

SHEET 2 OF 2 INVENTO J ATQRNEYS This invention relates to contact-breaker assemblies for use in ignition distributors.

A contact-breaker assembly according to the invention includes, an annular base plate arranged to be secured within the casing of an ignition distributor with the camshaft of the distributor extending through the hole in the base plate, a second plate mounted for pivotal movement on the base plate, and including a hollow bearing sleeve surrounding the camshaft and spaced therefrom, a body surrounding said sleeve and joumaled for angular movement thereon about the axis of the sleeve, a fixed contact secured to the body, a cam follower engageable with said camshaft, in use, through apertures in said body and said sleeve, and a movable contact resiliently urged into engagement with said fixed contact and movable out of engagement with said fixed contact by said cam follower in response to rotation of said camshaft relative to the cam follower.

One example of the invention is illustrated in the accompanying drawings, wherein FIG. 1 is a part sectional plan view of a contact-breaker assembly, and

FIG. 2 is a side elevational view of the assembly shown in FIG. 1.

Referring to the drawings, the contact-breaker assembly includes and annular base plate 11 which is arranged to be secured in the casing of an ignition distributor by any convenient means. The camshaft of the distributor extends upwardly through the central hole in the plate 11, the plate 11 being positioned in a plane at right angles to the axis of the camshaft. Pivotally connected to the base plate 11 at a point 12 (see FIG. 2) offset from the center of the hole in the plate 11 is a further plate 13. The plate 13 lies parallel to the plate H11, and is in sliding contact therewith, the plate 13 being formed with a circular hole of diameter substantially equal to the diameter of the hole in the plate 11, and so positioned in the plate 13, that it corresponds with the hole in the plate 11 in one angular position of the plate 13. In order to limit the range of angular movement of the plate 13 relative to the plate 11, the plate 13 is provided, adjacent its edge remote from the pivot 13 is point-l2 with an arcuate slot 14 through which a locking screw 15 extends. into screw-threaded engagement with the plate 11. Integral with the plate 13 and extending upwardly from the periphery of the hole in the plate 13 is a cylindrical sleeve 16, the camshaft of the distributor extending upwardly through the sleeve 16 in spaced relationship therewith in use.

The contact-breaker assembly further includes a metal body 17, through which the sleeve 16 extends. The body 17 is rotatably mounted on sleeve 16, the sleeve 16 constituting a cylindrical bearing for the body 17. Extending radially outwardly from the body 17 is an integral arm 18, and dependent from the arm 18 is a post 19. The post 19 extends into a slot 21 in the base plate 11, the end of the slot 21 cooperating with the post 19 to limit the permitted angular movement of the body 17 about the sleeve 16, relative to the base plate 11.

The body 17 is formed with a cylindrical recess 22 within which is housed a wound capacitor 23. The walls of the recess 22, constitutes the casing of the capacitor 23, and the windings of the capacitor 23 are insulated from the walls of the recess 22 by an insulating sleeve 24. One terminal of the capacitor 23 is electrically connected to a metal cover 26 through a first spring washer 25, the open end of the recess 22 being closed by the metal cover 26 which is secured to the body 17. In contact with the outer surface of the body 17 at the end of the recess 22 remote from the cover 26 is an insulating member 27 moulded in synthetic resin material. A hollow sleeve 28 integral-with the member 27 extends into an aperture in the body 17 and extending through the sleeve 28, so as to be insulated from the body 17 is a conductive terminal pin 29, the inner end of which is electrically connected to the other terminal of the capacitor 23 through a second spring washer 31. The spring washers 25, 31 act in opposite directions on the capacitor 23 to positively locate the capacitor 23 within the recess 22 and to ensure good electrical connections to the terminals of the capacitor.

Intermediate the ends of the pin 29, the pin includes an integral peripheral flange 32 which traps one end of a conductive leaf spring 33 against the member 27. The pin 29 extends through the leaf spring 33, and serves to electrically interconnect said other terminal of the capacitor 23 and the leaf spring 33. At its end remote from the pin 29 the leaf spring 33 carries the movable contact 34 of the contact-breaker assembly, and the spring 33 in its rest position, holds the movable contact 34 in engagement with the fixed contact 35 of the assembly The fixed 35 is carried by a resilient conductive plate 36 which is secured at one end to the body 17 by a screw so as to be electrically connected to the body. The body beneath the free end of the plate 36 is cut away as shown at 17a so that the plate 36 can flex as the contact 34 engages the contact 35, the flexure of the plate 36 imparting a wiping action to the mating surfaces of the contacts 34, 35 which cleans said surfaces and also serves to dissipate the kinetic energy of the contactbreaker assembly.

The insulating member 27 includes an integral resilient strip-like portion 37 which at its end remote from the capacitor 23 includes an integral cam follower 38. One end of the cam follower, which extend generally at right angles to the remainder of the strip 37, engages the leaf spring 33, while the other end of the cam follower 38 extends through an aperture 39 in the body 17, and a correspondingly positioned aperture 41 in the sleeve 16, so as to lie in the path of movement of the lobes of the camshaft of the distributor in use.

In use, when the contact breaker is utilized in an ignition distributor, the body 17 is earthed through a conductive braid 42 which is welded to the plate 36, and thus, the fixed contact 35, and said one terminal of the capacitor 23 are also connected to earth. The other terminal of the capacitor 23, and the movable contact 34 are electrically connected through the primary winding of an ignition coil, in the ignition system of the vehicle to one pole of the battery of the vehicle, the other pole of the battery being earthed. The connection to said other terminal of the capacitor 23 and to the movable contact 34, from the primary winding of the ignition coil, is made by way of a lead which is engaged with a spigot 43 integral with the flange 32 of the pin 29. The lead carries a connector which engages the spigot 43, and which is trapped between the flange 32 and a head on the free end of the spigot 43, the connection to said other terminal of the capacitor 23 being made through the pin 29 and the spring washer 31 and the connection to the movable contact 34 being made through the flange 32 of the pin 29, and the spring 33. Further an insulating sealing washer 44 is trapped between the spring washer 31 and the body 17 to insulate the windings of the capacitor 23 from the body 17, the washer 44 also serving to prevent ingress of foreign material into the recess 22.

As the camshaft of the distributor is rotated, the lobes of the camshaft engage the cam follower 38, in turn and move the cam follower as permitted by flexure of the strip 37, radially outwardly thereby moving the contact 34 out of engagement with the contact 35 and breaking the circuit through the primary winding of the ignition coil. In order to adjust the maximum. operating gap between the contacts 34, 35, the screw 25 is released, and the plate 23 is pivoted about the pivot 12 relative to the plate 11. A measuring device, such as a feeler gauge is inserted between the contacts 34, 35 when the cam follower 38 is engaged on a lobe of the camshaft, and the screw 15 is tightened to clamp the plate 13in position when the gap between the contacts 34,35 is correct.

The ignition distributor is provided with a vacuumadvance capsule for advancing and retarding the opening and closing of the contacts 34,35 in relation to the angular position of the crankshaft of the engine in accordance with the depression in the inlet manifold of the engine. The vacuum capsule is of conventional form, and includes a diaphragm, the position of which is moved in accordance with variation in the manifold depression, and the diaphragm of the vacuum capsule is connected to the post 19 by means of an inextensible connecting rod. Thus, as the manifold depression alters, the body 17 is caused to pivot about the sleeve 16, thereby moving the cam follower 38 and the contacts 34, 35 relative to the camshaft of the distributor. 1

Having thus described my invention what I claim as new and desire to secure by Letters Patent is 1. A contact-breaker assembly including an annular base plate arranged to be secured within the casing of an ignition distributor with the camshaft of the distributor extending through the hole in the base plate, a second plate mounted for pivotal movement on the base plate, and including a hollow bearing sleeve surrounding the camshaft and spaced therefrom, a body surrounding said sleeve and journaled for angular movement thereon about the axis of the sleeve, a resilient, third plate secured at one end to said body, a fixed contact carried by the third plate, a cam follower engageable with said camshaft, in use, through apertures in said body and said sleeve, and a movable contact resiliently urged into engagement with said fixed contact and movable out of engagement with said fixed contact by said cam follower in response to rotation of the cam shaft relative to the cam follower, and said body being cut away adjacent the free end of said resilient, third plate so that said third plate can flex when the movable contact engages the fixed contact in use.

2. An assembly as claimed in claim 1 within said body defines a cylindrical recess containing a capacitor.

' 3. An assembly as claimed in claim 2 wherein the open end of the recess is closed by a metal cover, said capacitor being resiliently held in position in the recess by a pair of spring washers acting against the body and said cover respectively and electrically connected to respective terminals of the capacitor.

4. An assembly as claimed in claim 2 wherein said cam follower is fonned as an integral part of a flexible insulating member, a conductive pin being carried by the insulating member and engaging one terminal of the capacitor, the movable contact being supported by said pin so that said pin 7 electrically interconnects said movable contact and said one terminal of the capacitor. 

1. A contact-breaker assembly including an annular base plate arranged to be secured within the casing of an ignition distributor with the camshaft of the distributor extending through the hole in the base plate, a second plate mounted for pivotal movement on the base plate, and including a hollow bearing sleeve surrounding the camshaft and spaced therefrom, a body surrounding said sleeve and journalled for angular movement thereon about the axis of the sleeve, a resilient, third plate secured at one end to said body, a fixed contact carried by the third plate, a cam follower engageable with said camshaft, in use, through apertures in said body and said sleeve, and a movable contact resiliently urged into engagement with said fixed contact and movable out of engagement with said fixed contact by said cam follower in response to rotation of the cam shaft relative to the cam follower, and said body being cut away adjacent the free end of said resilient, third plate so that said third plate can flex when the movable contact engages the fixed contact in use.
 2. An assembly as claimed in claim 1 within said body defines a cylindrical recess containing a capacitor.
 3. An assembly as claimed in claim 2 wherein the open end of the recess is closed by a metal cover, said capacitor being resiliently held in position in the recess by a pair of spring washers acting against the body and said cover respectively and electrically connected to respective terminals of the capacitor.
 4. An assembly as claimed in claim 2 wherein said cam follower is formed as an integral part of a flexible insulating member, a conductive pin being carried by the insulating member and engaging one terminal of the capacitor, the movable contact being supported by said pin so that said pin electrically interconnects said movable contact and said one terminal of the capacitor. 